Gating traffic into congested areas

It is possible to use fixed time UTC systems to restrict traffic but it is necessary to calculate the restraint timings by hand, an expensive procedure. However, within version 2.4 of SCOOT there is a facility to restrict traffic, the `gating´ facility, in response to demand on particular `bottleneck´ links within the controlled network. When the saturation on a bottleneck link rises above a threshold, then the green time is reduced on defined gated links. The gated links can be at some distance from the bottleneck; the first time that `action at a distance´ has been included in SCOOT. In fact the gated links can be anywhere in the controlled network, but stability problems are expected if they are a long way from the associated bottleneck